The proposed research will study the circulatory system which has evolved to nourish and to protect the transparent and neural structures of the eye. Methods will be employed to measure the rate of flow of aqueous humor in the human eye, methods which depend on fluorescent tracers and which are independent of pressure, resistance, or the stress-strain relations of the eye. Flow will be studied in human eyes to determine what role it plays in the intact eye in the regulation of intraocular pressure and how flow itself can be regulated. New techniques employing fluorescent probes are proposed to measure pH, oxygen concentration, and colloid concentration in the cornea and the anterior chamber. Studies of a number of clinical disorders will be carried out both to reveal the ocular adaptations to the disease and to characterize the disease. The conditions to be studied are unilateral Horner's syndrome, unilateral carotid occlusion, open angle glaucoma, ocular hypertension, low tension glaucoma, uveitis, and pigmentary glaucoma. The effects of adrenergic drugs on aqueous humor and other drugs whose effects are mediated by cAMP will be studied.